<template>
  <div class="goods">
    <div class="menu-wrapper" ref="menuwrapper">
      <ul>
        <li
          v-for="(item, index) in goods"
          :key="index"
          class="menu-item"
          :class="{'current':currentIndex === index}"
          @click="selectMenu(index, $event)"
        ><!-- 如果currentIndex与index相同则给li添加一个current的class名 -->
          <span class="text border-bottom">
            <span
              v-show="item.type > 0"
              class="icon" :class="classMap[item.type]"
            ></span>{{item.name}}
          </span>
        </li>
      </ul>
    </div>
    <div class="foods-wrapper" ref="foodwrapper">
      <ul>
        <li v-for="(item, index) in goods" :key="index" class="food-list food-list-hook">
          <h1 class="title">{{item.name}}</h1>
          <ul>
            <li v-for="(food, index) in item.foods" :key="index" class="food-item border-bottom">
              <div class="icon">
                <img width="57" height="57" :src="food.icon">
              </div>
              <div class="content">
                <h2 class="name">{{food.name}}</h2>
                <p class="desc">{{food.description}}</p>
                <div class="extra">
                  <span class="count">月售{{food.sellCount}}份</span>
                  <span>好评率{{food.rating}}%</span>
                </div>
                <div class="price">
                  <span class="now">￥{{food.price}}</span>
                  <span class="old" v-show="food.oldPrice">￥{{food.oldPrice}}</span>
                </div>
                <div class="cartcontrol-wrapper">
                  <cart-con-trol @cart-add="cartAdd" :food="food"></cart-con-trol>
                </div>
              </div>
            </li>
          </ul>
        </li>
      </ul>
    </div>
    <shop-cart ref="shopcart" :select-foods="selectFoods" :delivery-price="seller.deliveryPrice" :min-price="seller.minPrice"></shop-cart>
  </div>
</template>

<script>
  import Bscroll from 'better-scroll'
  import ShopCart from '../../components/shopcart/ShopCart'
  import CartConTrol from '../../components/cartcontrol/CartConTrol'
  const ERR_OK = 0
  export default {
    name: 'Goods',
    props: {
      seller: {
        type: Object
      }
    },
    components: {
      ShopCart, CartConTrol
    },
    data () {
      return {
        goods: [],
        listHeight: [],
        scrollY: 0
      }
    },
    computed: {
        currentIndex () {
          for (let i = 0; i < this.listHeight.length; i++) {
            let height1 = this.listHeight[i]
            let height2 = this.listHeight[i + 1]
            if (!height2 || (this.scrollY >= height1 && this.scrollY < height2)) {
              return i
            }
          }
          return 0
        },
      selectFoods () { // 给shopcart中添加food数组
          let foods = []
          this.goods.forEach((good) => {
            good.foods.forEach((food) => {
              if (food.count) { // 如果food有count属性，则将food添加到foods中
                foods.push(food)
              }
            })
          })
        return foods
      }
    },
    created () {
      this.classMap = ['decrease', 'discount', 'special', 'invoice', 'guarantee']
      this.$http.get('api/goods').then((res) => {
        res = res.body
        if (res.errno === ERR_OK) {
            this.goods = res.data
            this.$nextTick(() => {
              this._calculateHeight()
            })
        }
      })
    },
    methods: { /* 计算高度 */
      _calculateHeight () {
        let FoodList = this.$refs.foodwrapper.getElementsByClassName('food-list-hook')
        let height = 0
        this.listHeight.push(height)
        for (let i = 0; i < FoodList.length; i++) {
          let item = FoodList[i]
          height += item.clientHeight // 每一个food框的高度
          this.listHeight.push(height)
        }
      },
      selectMenu (index, event) {
        if (!event._constructed) { // 取消pc浏览时触发的点击事件
          return
        }
        let foodList = this.$refs.foodwrapper.getElementsByClassName('food-list-hook')
        let el = foodList[index]
        this.foodsScroll.scrollToElement(el, 300)
      },
      cartAdd (target) {
        this.$nextTick(() => { // 回调函数异步执行，两个动画效果就不会卡顿了
          this.$refs.shopcart.drop(target)
        })
      }
    },
    mounted () { /*  页面滚动 */
        this.menuScroll = new Bscroll(this.$refs.menuwrapper, {
          click: true // 可以被点击
        })
        this.foodsScroll = new Bscroll(this.$refs.foodwrapper, {
          click: true,
          probeType: 3 // 在滚动时希望知道滚动的位置，监听滚动的位置
        })
        this.foodsScroll.on('scroll', (pos) => {
          this.scrollY = Math.abs(Math.round(pos.y))// pos为负值需要abs转换为正值，需要round取整
        })
      }
  }
</script>

<style lang="stylus" scoped>
  @import "../../common/stylus/mixin.styl"

    .goods
      display flex
      position absolute
      top 174px
      bottom 46px
      width 100%
      overflow hidden
      .menu-wrapper
        flex 0 0 80px/* 第一个参数为内容不足时缩放情况、 第二个参数为等分、第三个是占位空间*/
        width 80px
        background #f3f5f7
        .menu-item
          display table
          height 54px
          width 56px
          line-height 14px
          padding 0 12px
          &.current
            position relative
            z-index 10
            margin-top -1px
            background #fff
            font-weight 700
          .icon
            display inline-block
            vertical-align top
            width 12px
            height 12px
            margin-right 2px
            background-size 12px 12px
            background-repeat no-repeat

            &.decrease
              bg-image('decrease_3')

            &.discount
              bg-image('discount_3')

            &.guarantee
              bg-image('guarantee_3')

            &.invoice
              bg-image('invoice_3')

            &.special
              bg-image('special_3')
          .text
            display table-cell
            width 56px
            vertical-align middle
            font-size 12px
            border-bottom rgba(7, 17, 37, 0.1)
      .foods-wrapper
        flex 1
        .title
          padding-left 14px
          height 26px
          line-height 26px
          border-left 2px solid #d9dde1
          font-size 12px
          color rgb(147,153,159)
          background #f3f5f7
        .food-item
          display flex
          margin 18px
          padding-bottom 18px
          border-bottom rgba(7, 17, 37, 0.1)
          &:last-child
            margin-bottom 0
          .icon
            flex 0 0 57px
            margin-right 10px
          .content
            flex 1
            .name
              margin 2px 0 8px 0
              height 14px
              line-height 14px
              font-size 14px
              color rgb(7,17,27)
            .desc, .extra
              line-height 10px
              font-size 10px
              color rgb(147,153,159)
            .desc
              line-height 12px
              margin-bottom 8px
            .extra
              .count
                margin-right 12px
            .price
              font-weight 700
              line-height 24px
              .now
                margin-right 18px
                font-size 14px
                color rgb(240,20,20)
              .old
                text-decoration line-height
                font-size 10px
                color rgb(147,153,159)
            .cartcontrol-wrapper
              position absolute
              right 0
              bottom 12px
</style>
